As defenders, it is extremely dangerous to be ignorant of how attackers can disrupt our systems. Without a good understanding of the relative ease of certain attacks, it's easy to adopt poor policies and procedures. A good example of this is the tendency for some organizations to use invalid or "self-signed" certifications for SSL, an approach that both trains the user to ignore certificate warnings displayed by the browser and leaves connections vulnerable to man in the middle attacks. In this article, we illustrate how easy such attacks are to execute; we hope this will serve as an incentive to adopt defenses that not only seem secure, but actually are!